Illusions Fool Even the Blind

That bats use echolocation to navigate and to find food is well known. But some blind people use the technique, too, clicking their tongues and snapping fingers to help identify objects.

Now, a study reports that human echolocators can experience illusions, just as sighted individuals do.

Gavin Buckingham, a psychology lecturer at Heriot-Watt University in Scotland, and his colleagues at the University of Western Ontario asked 10 study subjects to pick up strings attached to three boxes of identical weight but different sizes.

Overwhelmingly, the sighted individuals succumbed to what is known as the “size-weight illusion.” The bigger boxes felt lighter to them.

Blind study subjects who picked up each of the three strings did not experience the illusion. They correctly surmised that the boxes were of equal weight.

APS Board Treasurer Robert Klatzky’s pioneering work on human perception in robotics and virtual environments has earned her Fellow status with the world’s largest organization of technical professionals… More